Negative chemical and electron impact ionization mass spectrometry is being used for quantitative analysis of chlorodibenzo-p-dioxins in dairy cow tissue extracts. These dioxins were also found in the pentachlorophenol treated lumber from the barns used to house these animals. The flame retardant Firemaster BP-6 has been subjected to chemical and toxicologic study. No evidence could be found for the presence of bromodibenzo-p-dioxins or bromodibenzofurans. The material analyzed was found to be contaminated with a few hundred ppm bromonaphthalenes. BIBLIOGRAPHIC REFERENCES: Hass, J.R., McConnell, E.E., and Harvan, D.J.: Chemical and Toxicologic Evaluation of firemaster BP-6. J. Food Agric. Chem. (In press, 1977).